1. Field of the Invention
This invention relates to tire-mounted air pressure gauges, and specifically to an adapter assembly for allowing easy readability of such gauges on all vehicle tires, including the inner and outer tires on dual wheels.
2. Description of the Prior Art
Maintaining proper inflation of tires is critical for achieving optimum performance in vehicles and keeping operating costs low. Proper inflation increases fuel economy and performance and prolongs tire life. Indeed, a leading cause of the tire failure is underinflation. In addition, government regulations sometimes require careful monitoring of tire inflation and conditions (e.g., on vehicles which are transporting hazardous materials).
Most inflatable tires must have pressure checked by removing a cap from the valve stem and placing a pressure gauge on the valve stem. The pressure gauge depresses the valve core of the valve stem to allow air to escape from the tire and give a reading on the gauge. Once a tire's pressure has been evaluated, the cap must then be replaced and the process repeated for each tire. This involves substantial time and is very difficult when the vehicles involved are semitractor-trailers where the valve stems on some tires are not readily accessible (and there are eighteen inflated tires to check). In dual-wheel arrangements, the job of checking the pressure on all tires is particularly difficult. One attempt to remedy this difficulty is shown in U.S. Pat. No. 4,644,317, where pressure gauges were mounted on the tire of each wheel and a complicated system using electrical impulses was employed to send readings to the driver and check pressure differences between two adjacent tires. Other tire-mountable air pressure gauges are difficult to read because access to the valve stem of the inner tire of a dual-wheel assembly at the close range required for reading the gauge is not easy. The reader must bend down to the tire and work or peer through one or more apertures in the outer wheel.